I have summarized below the article I've read in toilet training children: 10 ways to prepare your child for the potty
Take your child into the bathroom with you. It's especially helpful if fathers and brothers set the example for boys, and mothers and sisters set the example for girls.
Try to help your child recognize the sensations of "being wet," "wetting now," and "about to be wet." Encourage your child to talk about these sensations -- especially "about to be..." sensations -- without pressing your child to be toilet trained.
Let your child go nude in appropriate settings to help the child " see" what he or she is doing, and to help make the mental connection between the words and what they refer to.
Changing a diaper in the bathroom will also associate the process with the place. Children over age 2 should be off the changing table for this reason.
Although much ado has been made about using the proper terminology for body parts and functions, you should use the words that come most easily to you and your child.
Help your child learn the meaning of the terms "before" and " after" by using them yourself in other contexts such as, "We'll wash the dishes after dinner."
Talk about the advantages of being trained: no more diaper rash, no more interruptions for diaper changing, the pleasure of being clean and dry.
Let your child practice lowering and raising training pants sometimes, or putting them on and taking them off.
Have a potty chair handy on which the child may sit (even with clothes on) perhaps while you are in the bathroom yourself, but only if he or she wants to.
Begin reading "potty" books to your child.